The present disclosure relates generally to biopsy systems and specifically to devices for obtaining biopsy samples through veins and arteries.
In the practice of diagnostic medicine, it is often necessary or desirable to perform a biopsy, or to sample selected tissue from a living patient for medical evaluation. Cytological and histological studies of the biopsy sample can then be performed as an aid to diagnosing and treating various forms of cancer, as well as other diseases in which a localized area of affected tissue can be identified.
Special considerations apply if the biopsy is to be performed on an internal organ deep within the body, such as the liver. Previously, obtaining a tissue sample from an internal organ, such as the liver, was carried out percutaneously by entering the skin in the vicinity of the organ and thereafter extracting a core of liver material through the biopsy needle. This method, although effective in obtaining an adequate amount of tissue from the liver, has a risk of serious health complications to the patient caused by the biopsy. For example, patients generally experience extreme pain, and additionally, the liver profusely bleeds after a percutaneous biopsy.
Alternatively, tissue samples may be obtained without the problems associated with a percutaneous biopsy by accessing the liver via a transjugular procedure. Known techniques involve accessing the liver through the jugular vein with an elongated biopsy device. Typically, these biopsy devices are identical to typical single and double action biopsy devices, except that the inner and outer needles are elongated to access the liver from the jugular vein.
A problem associated with this type of biopsy device is that the rigid inner and outer needles are commonly metallic and lack the flexibility to navigate through venous passageways to the targeted tissue site. However, biopsy of an organ deep within the body, such as the liver, requires the biopsy device to be implanted at a significant depth. Since the quality of the specimen is largely dependent on the striking momentum of the biopsy device over this long distance, a degree of stiffness of the needles is necessary to transmit striking force from the firing device to the tip of the coring needles. Thus, what is needed is a needle assembly that provides flexibility without compromising the stiffness and integrity of the needles.